Wind Patterns Create Pollution Hotspots in Cities

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Urban breezes disperse pollutants in specific patterns, rather
than randomly scattering the particles, suggesting that some
parts of cities become natural hotspots for contamination, new
research finds.

Researchers used a new mathematical model to simulate the random
motion of
pollutants — like exhaust particles, diesel fumes and
chemical residues — as would be found in the
real world, and they looked for coherent dispersal patterns.

"In previous studies, the existence of these patterns in fluid
flows was only verified with idealized 'theoretical' flows,'"
researcher Wenbo Tang, of Arizona State University in Tempe, said
in a statement. "It was not known if such structures were robust
enough to manifest in the environment."

But Tang and his colleagues found that patterns indeed emerged
from the movement of particles carried by these wind flows,
according to the American Institute of Physics, which recently
published the research in its journal Physics of Fluids. The
researchers said their formula might be used to map which regions
of a city are most susceptible to
high concentrations of pollutants, which, in turn, could help
policymakers decide how to deal with particularly hazardous or
vulnerable areas.